Parallel creation is one of the hazards of a creative professional career. Ideas are memetic so it's no surprise that people are often working on the same topic at the same time. My slow production cycle means I've often gotten bitten by it and I know I've bitten others. I came across this video by Jake of Vsauce3 talking about the transporter paradox video he intended to release today... but... yeah.
It's a sucky situation with no one at fault and no easy answer of what to do. As such I wrote a letter this morning to Jake trying to express my thoughts: